Lung and kidney perfusion deficits diagnosed by dual-energy computed tomography in patients with COVID-19-related systemic microangiopathy.

OBJECTIVES: There is increasing evidence that thrombotic events occur in patients with coronavirus disease (COVID-19). We evaluated lung and kidney perfusion abnormalities in patients with COVID-19 by dual-energy computed tomography (DECT) and investigated the role of perfusion abnormalities on disease severity as a sign of microvascular obstruction. METHODS: Thirty-one patients with COVID-19 who underwent pulmonary DECT angiography and were suspected of having pulmonary thromboembolism were included. Pulmonary and kidney images were reviewed. Patient characteristics and laboratory findings were compared between those with and without lung perfusion deficits (PDs). RESULTS: DECT images showed PDs in eight patients (25.8%), which were not overlapping with areas of ground-glass opacity or consolidation. Among these patients, two had pulmonary thromboembolism confirmed by CT angiography. Patients with PDs had a longer hospital stay (p = 0.14), higher intensive care unit admission rates (p = 0.02), and more severe disease (p = 0.01). In the PD group, serum ferritin, aspartate aminotransferase, fibrinogen, D-dimer, C-reactive protein, and troponin levels were significantly higher, whereas albumin level was lower (p < 0.05). D-dimer levels ≥ 0.485 µg/L predicted PD with 100% specificity and 87% sensitivity. Renal iodine maps showed heterogeneous enhancement consistent with perfusion abnormalities in 13 patients (50%) with lower sodium levels (p = 0.03). CONCLUSIONS: We found that a large proportion of patients with mild-to-moderate COVID-19 had PDs in their lungs and kidneys, which may be suggestive of the presence of systemic microangiopathy with micro-thrombosis. These findings help in understanding the physiology of hypoxemia and may have implications in the management of patients with COVID-19, such as early indications of thromboprophylaxis or anticoagulants and optimizing oxygenation strategies. KEY POINTS: • Pulmonary perfusion abnormalities in COVID-19 patients, associated with disease severity, can be detected by pulmonary DECT. • A cutoff value of 0.485 µg/L for D-dimer plasma levels predicted lung perfusion deficits with 100% specificity and 87% sensitivity (AUROC, 0.957). • Perfusion abnormalities in the kidney are suggestive of a subclinical systemic microvascular obstruction in these patients.

AI-Based Quantitative CT Analysis of Temporal Changes According to Disease Severity in COVID-19 Pneumonia.

OBJECTIVE: To quantitatively evaluate computed tomography (CT) parameters of coronavirus disease 2019 (COVID-19) pneumonia an artificial intelligence (AI)-based software in different clinical severity groups during the disease course. METHODS: From March 11 to April 15, 2020, 51 patients (age, 18-84 years; 28 men) diagnosed and hospitalized with COVID-19 pneumonia with a total of 116 CT scans were enrolled in the study. Patients were divided into mild (n = 12), moderate (n = 31), and severe (n = 8) groups based on clinical severity. An AI-based quantitative CT analysis, including lung volume, opacity score, opacity volume, percentage of opacity, and mean lung density, was performed in initial and follow-up CTs obtained at different time points. Receiver operating characteristic analysis was performed to find the diagnostic ability of quantitative CT parameters for discriminating severe from nonsevere pneumonia. RESULTS: In baseline assessment, the severe group had significantly higher opacity score, opacity volume, higher percentage of opacity, and higher mean lung density than the moderate group (all P ≤ 0.001). Through consecutive time points, the severe group had a significant decrease in lung volume (P = 0.006), a significant increase in total opacity score (P = 0.003), and percentage of opacity (P = 0.007). A significant increase in total opacity score was also observed for the mild group (P = 0.011). Residual opacities were observed in all groups. The involvement of more than 4 lobes (sensitivity, 100%; specificity, 65.26%), total opacity score greater than 4 (sensitivity, 100%; specificity, 64.21), total opacity volume greater than 337.4 mL (sensitivity, 80.95%; specificity, 84.21%), percentage of opacity greater than 11% (sensitivity, 80.95%; specificity, 88.42%), total high opacity volume greater than 10.5 mL (sensitivity, 95.24%; specificity, 66.32%), percentage of high opacity greater than 0.8% (sensitivity, 85.71%; specificity, 80.00%) and mean lung density HU greater than -705 HU (sensitivity, 57.14%; specificity, 90.53%) were related to severe pneumonia. CONCLUSIONS: An AI-based quantitative CT analysis is an objective tool in demonstrating disease severity and can also assist the clinician in follow-up by providing information about the disease course and prognosis according to different clinical severity groups.

An unusual presentation of pulmonary artery sarcoma: Several pseudoaneurysms with massive hemoptysis.

A 53-year-old woman was admitted to the emergency department with sudden onset of massive hemoptysis. She had previous history of dyspnea and cough for two months. She had no history of chronic disease, smoking, or use of anticoagulant and antiplatelet drugs. On arrival, she was tachycardic and tachypneic, but her body temperature was normal. Chest X-ray showed enlarged right hilus and multiple nodular opacities predominantly in the left lung basis. Computed tomography (CT) scan of the chest demonstrated massive intraluminal filling defect extending from the right pulmonary artery through the main and left pulmonary arteries. Pulmonary artery sarcoma (PAS) was the preliminary imaging-based diagnosis. However, CT also revealed presence of several pseudoaneurysms arising from the distal branches of the left pulmonary artery encased by metastatic nodules. Although hemoptysis is an uncommon presentation for patients with PAS, accompanied pseudoaneurysms were the main reason for massive hemoptysis. Differentiation of PAS from bland thromboembolism could be challenging on CT. Herein reported case provides an additional imaging feature that may utilize differentiating pulmonary artery sarcoma from bland thrombus.

Axial pulmonary trunk diameter variations during the cardiac cycle.

PURPOSE: Previous studies have shown a correlation between axial pulmonary trunk diameter (PTD) on chest computed tomography (CT) and pulmonary artery pressure. However, it is not known whether the PTD slices measured on chest CT have been recorded during the systolic or diastolic phase. The aim of this study was to demonstrate the variations in PTD during the cardiac cycle by measuring coronary CT angiography (CCTA) images. METHODS: A retrospective analysis was made of 101 patients who underwent CCTA for coronary artery disease assessment. CCTA images were reconstructed during a full cardiac cycle and measurements were taken of the systolic and diastolic PTD and ascending aorta diameter (AAD) from the same slice by two independent observers. RESULTS: Inter-observer agreement was excellent (intraclass correlation coefficient = 0.99) for all CT measurements. The mean systolic PTD of all patients was 26.3 ± 3.6 mm and the mean diastolic PTD was 22.8 ± 3.2 mm (p < 0.001). The mean difference between systole and diastole was found to be 3.5 ± 1.2 mm for PTD, 1.2 ± 0.7 mm for AAD, and 0.1 ± 0.04 for the PTD/AAD ratio (p values < 0.001). There was no statistical significance of PTD variations according to gender, age, height, weight, body mass index, and body surface area. CONCLUSION: When an increased PTD is detected in a chest CT compared to normal limits or a previous CT scan, this may be the result of the variation in PTD due to the cardiac cycle.

MDCT evaluation of sternal development.

BACKGROUND AND PURPOSE: Sternal ossification starts in utero, and continues throughout puberty in various patterns. In this study, our objective was to evaluate the correlation of ossification with age and to determine whether age can be predicted. MATERIALS AND METHODS: Individuals younger than 30 years old without congenital anomalies, chronic disease, and history of long-term chemotherapy who had chest CT imaging with a slice thickness < 3 mm were retrospectively reviewed. Data of ossification centers, horizontal and vertical fusion were collected. Spearman correlation test and ROC analysis were performed to correlate age with fusion. Kruskal-Wallis test was used to perform gender wise comparisons. Sensitivity, specificity, positive predictive value and negative predictive value of cut-off points, estimated according to ROC analysis, were calculated. RESULTS: Segmented ossification centers were more common in males, with significant difference in third and fourth mesosternal ossification centers (p < 0.05). Females had more vertical fusion at each level (p < 0.05). Spearman correlation test showed significant correlation between age and horizontal and vertical fusion for both genders. ROC analysis was performed and cut-off values were estimated. Sensitivity was very high (84.6-100%) but specificity was low (43.3-79.9%) for horizontal fusion. Sensitivity of vertical fusion (64.8-100%) was similar but specificity was higher (74.7-100%). CONCLUSIONS: Horizontal and vertical fusions of sternal ossification centers correlate with age significantly. Vertical fusion might be a better indicator of age with higher sensitivity and specificity, while horizontal fusion has lower accuracy. Large-scale studies should be conducted to confirm our results.

Nonthrombotic Pulmonary Artery Embolism: Imaging Findings and Review of the Literature.

OBJECTIVE: The purpose of this article is to emphasize the imaging findings encountered in the setting of nonthrombotic pulmonary embolism. CONCLUSION: Nonthrombotic pulmonary embolism refers to a spectrum of clinical and radiologic disorders caused by embolization of the pulmonary artery vasculature by various cell types, microorganism, and foreign bodies. Awareness of the imaging and clinical features of the nonthrombotic pulmonary embolism may facilitate prompt diagnosis.

Circumaortic doubled left brachiocephalic vein: a rare confusing variation.

Left brachiocephalic vein (LBCV), one of the major veins draining upper extremity, head and neck region, has rare anatomic variations. Circumaortic type, an extremely uncommon variation, is presented here; this was incidentally detected on computed tomography images. In this case, circumaortic LBCV had two branches; one was normally placed brachiocephalic vein anterior to the aortic arch, and the other one was the anomalous branch with a retroaortic course.

Costovertebral and costotransverse joint involvement in spondyloarthritis.

OBJECTIVES: Costovertebral (CV), costotransverse (CTr), sternoclavicular (SC), and manubriosternal (MS) joints are impacted in spondyloarthritis (SpA) patients; however, clinical aspects of these involvements require additional evaluation. METHODS: A total of 281 SpA patients who had undergone chest computed tomography (CT) for any reason between 2010 and 2020 were included in the study. SpA patients were divided into three groups, ankylosing spondylitis (AS), non-radiographic axial SpA, and psoriatic arthritis. Thirty age- and sex-matched rheumatoid arthritis (RA) patients and 30 non-rheumatic disease individuals were selected for comparison. An experienced radiologist reviewed 24 CV, 20 CTr, 2 SC, and 1 MS joints from a thorax CT for each patient. All joints were classified as: normal (0); suspicious (1), mild (2), moderate (3), or severe (4). RESULTS: Total CV and CTr joint scores differed between diseases (p < .001). Male AS patients had higher CV and CTr scores than female AS patients (male CV score: 52 [range 0-96] and CTr score: 22 [range 0-80]; female CV score: 20 [range 0-96] and CTr score: 12 [range 0-79]). Strong negative correlations were detected in AS patients between chest expansion and CV (r = -0.703 p = .007) and CTr (r = -0.763 p = .002) joint involvement; positive correlations between CV and CTr joints, and modified Stoke Ankylosing Spondylitis Spinal Score (p < .05); and no significant association for MS and SC joints. CONCLUSIONS: CV and CTr joint involvement on thorax CT was more severe in AS and negatively affected chest expansion. The use of thorax CT scans performed for other indications in the examination of these joints may be advantageous for the early beginning of rehabilitation programs targeted at maintaining chest mobility.

Two in one: Overlapping CT findings of COVID-19 and underlying lung diseases.

Coronavirus disease 2019 (COVID-19) is associated with pneumonia and has various pulmonary manifestations on computed tomography (CT). Although COVID-19 pneumonia is usually seen as bilateral predominantly peripheral ground-glass opacities with or without consolidation, it can present with atypical radiological findings and resemble the imaging findings of other lung diseases. Diagnosis of COVID-19 pneumonia is much more challenging for both clinicians and radiologists in the presence of pre-existing lung disease. The imaging features of COVID-19 and underlying lung disease can overlap and obscure the findings of each other. Knowledge of the radiological findings of both diseases and possible complications, correct diagnosis, and multidisciplinary consensus play key roles in the appropriate management of diseases. In this pictorial review, the chest CT findings are presented of patients with underlying lung diseases and overlapping COVID-19 pneumonia and the various reasons for radiological lung abnormalities in these patients are discussed.

Nerves of the Thorax: Anatomy, Clinical Signs, and Imaging Findings of Pathological Conditions.

BACKGROUND: Radiological diagnosis of thoracic nerve diseases is difficult because they are rare, and nerves cannot be seen directly on radiological images. The major nerves of the thorax can be listed as the phrenic, vagus, recurrent laryngeal, long thoracic nerve pairs, sympathetic chains, costal nerves, and brachial plexus. Diseases of thoracic nerves have various causes, including traumatic injury, neuromuscular diseases, infection, compression, radiation, drugs, and tumors. OBJECTIVE: This pictorial review aims to describe the anatomic locations of the major thoracic nerves on radiological images, comprehensively describe the causes of thoracic nerve diseases and define the clinical signs and primary and secondary imaging findings of dysfunction of the thoracic nerves. METHODS: This paper was designed to illustrate primary and secondary imaging findings of nerve diseases. Firstly, the normal anatomy of nerves is shown with diagrams. Secondly, we explained primary and secondary imaging features with variable radiological methods, including chest X-Ray, magnetic resonance imaging, and computed tomography. CONCLUSION: Primary findings of nerve diseases can be detected if radiologists are familiar with the courses of the nerves on radiological images. Knowledge of the normal functions of the nerves can aid in diagnosing thoracic nerve diseases identified from secondary imaging findings such as diaphragmatic elevation, muscular atrophy, and winged scapula. It is essential to know the normal anatomy, function, and possible causes of thoracic nerve diseases to make a correct diagnosis and apply the prompt treatment.

Errors, discrepancies and underlying bias in radiology with case examples: a pictorial review.

Interpretation differences between radiologists and diagnostic errors are significant issues in daily radiology practice. An awareness of errors and their underlying causes can potentially increase the diagnostic performance and reduce individual harm. The aim of this paper is to review both the classification of errors and the underlying biases. Case-based examples are presented and discussed for each type of error and bias to provide greater clarity and understanding.

Imaging of congenital lung diseases presenting in the adulthood: a pictorial review.

Congenital lung diseases in adults are rare diseases that can present with symptoms or be detected incidentally. Familiarity with the imaging features of different types of congenital lung diseases helps both in correct diagnosis and management of these diseases. Congenital lung diseases in adults are classified into three main categories as bronchopulmonary anomalies, vascular anomalies, and combined bronchopulmonary and vascular anomalies. Contrast-enhanced computed tomography, especially 3D reconstructions, CT, or MR angiography, can show vascular anomalies in detail. The tracheobronchial tree, parenchymal changes, and possible complications can also be defined on chest CT, and new applications such as quantitative 3D reconstruction CT images, dual-energy CT (DECT) can be helpful in imaging parenchymal changes. In addition to the morphological assessment of the lungs, novel MRI techniques such as ultra-short echo time (UTE), arterial spin labeling (ASL), and phase-resolved functional lung (PREFUL) can provide functional information. This pictorial review aims to comprehensively define the radiological characteristics of each congenital lung disease in adults and to highlight differential diagnoses and possible complications of these diseases.

COVID-19 pneumonia: the great radiological mimicker.

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has rapidly spread worldwide since December 2019. Although the reference diagnostic test is a real-time reverse transcription-polymerase chain reaction (RT-PCR), chest-computed tomography (CT) has been frequently used in diagnosis because of the low sensitivity rates of RT-PCR. CT findings of COVID-19 are well described in the literature and include predominantly peripheral, bilateral ground-glass opacities (GGOs), combination of GGOs with consolidations, and/or septal thickening creating a "crazy-paving" pattern. Longitudinal changes of typical CT findings and less reported findings (air bronchograms, CT halo sign, and reverse halo sign) may mimic a wide range of lung pathologies radiologically. Moreover, accompanying and underlying lung abnormalities may interfere with the CT findings of COVID-19 pneumonia. The diseases that COVID-19 pneumonia may mimic can be broadly classified as infectious or non-infectious diseases (pulmonary edema, hemorrhage, neoplasms, organizing pneumonia, pulmonary alveolar proteinosis, sarcoidosis, pulmonary infarction, interstitial lung diseases, and aspiration pneumonia). We summarize the imaging findings of COVID-19 and the aforementioned lung pathologies that COVID-19 pneumonia may mimic. We also discuss the features that may aid in the differential diagnosis, as the disease continues to spread and will be one of our main differential diagnoses some time more.

Radiological manifestations of thoracic hydatid cysts: pulmonary and extrapulmonary findings.

Hydatid cyst caused by the larval form of Echinococcus is a worldwide zoonosis. The lungs and liver are the most common sites involved. While the lung parenchyma is the most common site within the thorax, it may develop in any extrapulmonary region including the pleural cavity, fissures, mediastinum, heart, vascular structures, chest wall, and diaphragm. Imaging plays a pivotal role not only in the diagnosis of hydatid cyst, but also in the visualization of the extent of involvement and complications. The aim of this pictorial review was to comprehensively describe the imaging findings of thoracic hydatid cyst including pulmonary and very unusual extrapulmonary involvements. An outline is also given for the findings of complications and differential diagnosis of thoracic hydatid cyst.

Visual and software-based quantitative chest CT assessment of COVID-19: correlation with clinical findings.

PURPOSE: The aim of this study was to evaluate visual and software-based quantitative assessment of parenchymal changes and normal lung parenchyma in patients with coronavirus disease 2019 (COVID-19) pneumonia. The secondary aim of the study was to compare the radiologic findings with clinical and laboratory data. METHODS: Patients with COVID-19 who underwent chest computed tomography (CT) between March 11, 2020 and April 15, 2020 were retrospectively evaluated. Clinical and laboratory findings of patients with abnormal findings on chest CT and PCR-evidence of COVID-19 infection were recorded. Visual quantitative assessment score (VQAS) was performed according to the extent of lung opacities. Software-based quantitative assessment of the normal lung parenchyma percentage (SQNLP) was automatically quantified by a deep learning software. The presence of consolidation and crazy paving pattern (CPP) was also recorded. Statistical analyses were performed to evaluate the correlation between quantitative radiologic assessments, and clinical and laboratory findings, as well as to determine the predictive utility of radiologic findings for estimating severe pneumonia and admission to intensive care unit (ICU). RESULTS: A total of 90 patients were enrolled. Both VQAS and SQNLP were significantly correlated with multiple clinical parameters. While VQAS >8.5 (sensitivity, 84.2%; specificity, 80.3%) and SQNLP <82.45% (sensitivity, 83.1%; specificity, 84.2%) were related to severe pneumonia, VQAS >9.5 (sensitivity, 93.3%; specificity, 86.5%) and SQNLP <81.1% (sensitivity, 86.5%; specificity, 86.7%) were predictive of ICU admission. Both consolidation and CPP were more commonly seen in patients with severe pneumonia than patients with nonsevere pneumonia (P = 0.197 for consolidation; P < 0.001 for CPP). Moreover, the presence of CPP showed high specificity (97.2%) for severe pneumonia. CONCLUSION: Both SQNLP and VQAS were significantly related to the clinical findings, highlighting their clinical utility in predicting severe pneumonia, ICU admission, length of hospital stay, and management of the disease. On the other hand, presence of CPP has high specificity for severe COVID-19 pneumonia.

The imaging appearances of various pericardial disorders.

The pericardium could be involved in a variety of clinical disorders. The imaging findings are not specific for an individual pathology in most of the cases; however, patient's clinical history may guide radiologist to a definitive diagnosis. Congenital absence of the pericardium could be recognized with the imaging appearance of interposed lung tissue between the main pulmonary artery and aorta. Pericardial effusion is a non-specific condition that may occur due to inflammatory, infectious, and neoplastic disorders. Cardiac tamponade may occur in case of massive or rapid accumulation of fluid in the pericardial sac. Pericardial calcification is a common and easily identified entity on a computed tomography (CT) scan. Presence of calcification and/or fibrosis may result in pericardial constriction. Nevertheless, the pulsation of an adjacent coronary artery may prevent calcification formation in a focal area and consequently may result in pericardial diverticulum containing epicardial fat and coronary artery. The imaging findings encountered in patients with pericardial hydatid disease and Erdheim-Chester disease may mimic those of pericardial neoplasia. Pericardial adhesions and pedicled fat flaps may cause confusion on a CT scan in the post-surgical period following cardiac surgery. Pericardial fat necrosis can be diagnosed by CT in patients with chest pain. The radiologists should be familiar with the medical devices placed in pericardial space for certain individual indications. A pericardial patch and temporary epicardial pacemaker wires could be identified on a CT scan.

Reentrance of Azygos Vein into Azygos Fissure After Pneumothorax.

Empty azygos fissure implies dislocation of the azygos vein to the mediastinal side of the right upper lobe from azygos fissure, which is usually secondary to pneumothorax, pleural effusion, parenchymal fibrosis, vertebral collapse or persistent vomiting. We are presenting here a case where a separated azygos vein in CT and radiography images was noted. Moreover, in the follow-up images, it appeared that the complete reexpansion of the right lung resulted in reentrance of the azygos vein into azygos fissure in its native position.

Expansion of the Rib Head: A Novel Computed Tomographic Feature of Supernumerary Intrathoracic Ribs.

Intrathoracic ribs are very rare congenital anomalies. Approximately 50 cases have been reported in the literature till date. They are usually present on the right side, between the third and eighth ribs without sex predominance. They may originate from a vertebral body or the proximal or distal part of a rib. In most cases, they are asymptomatic, but they may be associated with developmental abnormalities of ribs and vertebrae. The diagnosis is important to prevent further investigation or intervention. Here we present two rare cases with supernumerary intrathoracic rib and describe a novel sign, namely expansion of the rib head. To the best of our knowledge, this is the shortest supernumerary intrathoracic rib, reported in the literature, on the left side originating from the head of the second rib, which could have been misdiagnosed as osteochondroma due to its atypical features.